Checking the calibration of an RF signal generator
Setting an RF signal generator on a crystal frequency
Finding the exact point of a zero beat
Test records: Good substitutes for the audio-signal generator
Using radio signals for testing stereo or PA systems
Using a communications receiver as an RF signal locator or tracer
The ac voltmeter for gain checks and signal tracing
Power output tests for PA and hi-fl amplifiers
10. Digital circuits ( coming
Monitoring brief digital signals
Signal tracing in a digital circuit
Digital signal shape
Power-supply problems in digital circuits
Noise and glitches
11. Flowcharting and troubleshooting ( coming
Servicing without a schematic
Systems comprised of multiple pieces of interconnected equipment
( coming soon)
Electronics encompasses those things we can neither hear, see, touch,
or taste. Electrical voltage, current, and resistance are in visible to
the senses. Of course, you can directly sense an electrical shock, but
to learn what’s going on within an electronic circuit, you must use test
equipment. Test equipment is special apparatus designed to give visible
or audible indications of what is there and what it’s doing.
Modern test instruments are amazingly versatile. They can do almost anything,
if you know how to use them, how they work, and what their limitations
are. If you don’t know how to use test equipment properly, it’s virtually
useless. It’s also just as important to know what a test instrument can’t
do. All test instruments can make the tests for which they are designed.
Most can make many other tests as well, if you know how the instruments
work and how their readings can indicate the presence or absence of other
That’s what this guide is about—electronic tests and measurements, how
to make them with all types of electronic test equipment, and how to interpret
the results. Interpretation is the most important part of the whole process.
It requires a full knowledge of both the test equipment and the circuits
in which we’re taking the readings.
Electronics is a rapidly growing field, with new developments appearing
almost daily. Although the basic principles of electronics theory remain
the same, often new technology calls for new test procedures. In this Guide,
every attempt has been made to provide as much up-to-date information as
possible. Now-obsolete test procedures involving tube circuits were featured
heavily in the original edition. This no-longer-relevant material has been
eliminated and replaced with expanded information on testing transistor,
and especially IC-based, circuitry.
The most important types of electronic test equipment are introduced in
section 1. The following two sections cover a wide variety of voltage and
current tests, some of which are less than obvious.
The two most widely used test instruments are the multi- meter (VOM, VTVM,
or DMM) and the oscilloscope. Basic and advanced test procedures using
these powerful test instruments are covered in sections 4 and 5.
At some point in servicing an electronic circuit, you will need to determine
whether or not a specific component has gone bad. Section
6 offers many
tips on testing various specific types of electronic components.
A number of test procedures for television circuits are given in section
7. Section 8 features a number of more or less unclassifiable special test
procedures, including tests for various types of semiconductors. Section
9 covers signal tracing and alignment tests.
Section 10, on digital circuits, has been significantly expanded in this
edition in response to the growing emphasis on dig ital circuitry in modern
commercial equipment of all types.
Finally, section 11 covers the important principles of flow- charting
and troubleshooting complex systems comprised of multiple circuits. This
information will help you pinpoint the problematic stage, saving a lot
of time that could be wasted in making unnecessary tests. Devoting a little
time to thinking about the circuit before you turn on your test equipment
will never be wasted time. In fact, in the long run, most servicing jobs
will go much faster.
As you will discover as you go through this guide, there are many shortcuts
— combinations of instruments and so forth — that you can use to test almost
any electrical quantity, even those that might not appear to be within
the range of your test equipment. A surprising number of electronic tests
can be made with little more than a pilot lamp, a neon lamp, or a dc voltmeter.
How ever, other tests require more sophisticated, arid expensive, equipment.
Although it’s obviously impossible for any single volume to cover every
possible type of electronic test procedure, our goal has been to offer
as wide a range of generally applicable procedures as possible. In updating
the material for this guide, we have tried to live up to the title as much
as possible and help the reader learn “how to test almost everything electronic.”